Add message decryption

Currently, this just takes a message from the text box and returns its
decrypted version, but next I will make it decrypt messages it gets from
relays.

This code works with both NIP-07 (window.nostr) and getPrivateKey().  If
both are available, it chooses NIP-07 like the encryption code.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/lib/nip17.ts b/src/lib/nip17.ts
index 6a9888b6..84790275 100644
--- a/src/lib/nip17.ts
+++ b/src/lib/nip17.ts
@@ -78,3 +78,14 @@ const giftWrap = (event: object, receiverPK: string) => {
 
     return finalizeEvent(giftWrapEvent, secretKey);
 }
+
+export const decryptNIP17MessageNIP07 = async (text: string): string => {
+    const wrapped = JSON.parse(text);
+    const sealedText = await window.nostr.nip44.decrypt(
+        wrapped.pubkey, wrapped.content);
+    const sealed = JSON.parse(sealedText);
+    const rumourText = await window.nostr.nip44.decrypt(
+        sealed.pubkey, sealed.content);
+    const rumour = JSON.parse(rumourText);
+    return rumour.content;
+}